Overview
- The Yonsei University team reports in MNRAS that correcting for a strong age-related bias in Type Ia supernova brightness removes evidence for present-day acceleration and implies time-varying, weakening dark energy.
- Analyzing about 300 host galaxies, the authors find younger progenitor populations yield systematically fainter supernovae while older populations appear brighter, a correlation they claim at 99.999% confidence.
- After the age correction, supernova distances no longer support the standard ΛCDM cosmological-constant model and align more closely with BAO+CMB results favored by DESI that indicate evolving dark energy.
- Combining the corrected supernova data with BAO and CMB measurements, the paper reports overwhelming rejection of ΛCDM and concludes the universe has already entered a phase of decelerated expansion.
- Independent researchers, including Adam Riess and Mark Sullivan, voice strong skepticism over the age estimates and prior related claims, and the Yonsei team is pursuing evolution-free tests with larger samples expected from the Vera C. Rubin Observatory.